/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License.  You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

package org.apache.poi.hssf.record.formula.eval;

import org.apache.poi.hssf.record.formula.ConcatPtg;
import org.apache.poi.hssf.record.formula.Ptg;

/**
 * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
 *  
 */
public final class ConcatEval extends StringOperationEval {

    private ConcatPtg delegate;

    public ConcatEval(Ptg ptg) {
        this.delegate = (ConcatPtg) ptg;
    }

    public Eval evaluate(Eval[] args, int srcRow, short srcCol) {
    	if(args.length != 2) {
    		return ErrorEval.VALUE_INVALID;
    	}
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < 2; i++) { 
            
            ValueEval ve = singleOperandEvaluate(args[i], srcRow, srcCol);
            if (ve instanceof StringValueEval) {
                StringValueEval sve = (StringValueEval) ve;
                sb.append(sve.getStringValue());
            }
            else if (ve instanceof BlankEval) {
                // do nothing
            }
            else { // must be an error eval
                return ve;
            }
        }
        
        return new StringEval(sb.toString());
    }

    public int getNumberOfOperands() {
        return delegate.getNumberOfOperands();
    }

    public int getType() {
        return delegate.getType();
    }
}
